The present invention generally relates to liquid heating apparatus and, in a preferred embodiment thereof, more particularly relates to a specially designed bottom pad/foam dam member positionable under the tank and outer jacket portions of a water heater.
As conventionally constructed, a water heater typically has a tank portion adapted to hold a quantity of water to be heated, an outer jacket structure outwardly circumscribing the vertical tank side wall portion and forming an annular insulation space therewith, and a quantity of insulation disposed in this annular space. The bottom end of the tank/jacket structure is typically placed into a circular bottom pan structure and suitably secured thereto.
A common method of placing insulation in the tank/jacket annulus, after a bottom portion of the tank/jacket structure secured within the bottom pan, is to simply inject liquid foam insulation into the annulus and let the injected foam cure therein. As is well known in this art, pressurized injected liquid insulation foam has an undesirable propensity for leaking out of the tank/jacket annulus--particularly at the interface between the bottom pan and the bottom tank/jacket portion received therein. In order to contain the injected liquid foam within the tank/jacket annulus, a variety of "dam" structures have previously been utilized to seal various leak paths leading outwardly from the annulus.
To block outward injected foam insulation leakage at the bottom pan, one proposed solution has been to install a bottom pad/foam dam member in the bottom pan and then rest the bottom end portion of the tank/jacket structure on the pad/dam member which is configured to block outward flow of injected foam insulation outwardly from the tank/jacket annulus adjacent the bottom pan. Examples of these previously proposed bottom pad/foam dam members may be found in U.S. Pat. No. 5,154,140 and Canadian Patent 2,062,015.
A primary disadvantage of these previously proposed bottom pad/foam dam members is that each is adapted for use only with a water heater having a certain tank diameter and jacket diameter. If a water heater having a different tank diameter is provided, a differently configured pad/dam member is required. Accordingly, in a given line of water heaters produced by a manufacturer and having different tank diameters, a differently configured pad/dam member has to be provided for each different water heater model. A need thus exists for a bottom pad/foam dam member which is not limited in this manner. It is to this need that the present invention is directed.